Negative electrode active material, negative electrode including the same, and secondary battery including the negative electrode
The present invention relates to a negative electrode active material including a spherical carbon-based particle, and a carbon layer disposed on the spherical carbon-based particle and including a nano-particle, wherein the nano-particle has a silicon core, an oxide layer disposed on the silicon core and including SiO x (0<x≤2), and a coating layer covering at least a portion of the surface of the oxide layer and including LiF.
1. A negative electrode active material comprising: a spherical carbon-based particle; and a carbon layer disposed on the spherical carbon-based particle and including a nano-particle, wherein
the nano-particle comprises a three-layered structure including:
a silicon core;
an oxide layer directly disposed on the silicon core and including SiO x (0<x≤2); and
a coating layer directly disposed on at least a portion of a surface of the oxide layer and including LiF,
wherein the spherical carbon-based particle is natural graphite,
wherein sphericity of the spherical carbon-based particle is from 0.55 to 0.95,
wherein the nano-particle is included in an amount of 1 wt % to 50 wt % based on a total weight of the negative electrode active material, and
wherein the LiF is included in an amount of 0.05 wt % to 12 wt % based on the total weight of the negative electrode active material.
2. The negative electrode active material of claim 1 , wherein an average particle diameter (D 50 ) of the silicon-core is from 40 nm to 400 nm.
3. The negative electrode active material of claim 1 , wherein a thickness of the oxide layer is from 0.01 nm to 20 nm.
4. The negative electrode active material of claim 1 , wherein the LiF is included in an amount of 0.01 wt % to 25 wt % based on a total weight of the negative electrode active material.
5. The negative electrode active material of claim 1 , wherein a thickness of the coating layer is from 0.01 nm to 50 nm.
6. The negative electrode active material of claim 1 , wherein an average particle diameter (D 50 ) of the spherical carbon-based particle is 2 μm to 50 μm.
7. The negative electrode active material of claim 1 , wherein the spherical carbon-based particle is included in an amount of 40 wt % to 95 wt % based on a total weight of the negative electrode active material.
8. The negative electrode active material of claim 1 , wherein a weight ratio of the spherical carbon-based particle to the nano-particle is 98:2 to 50:50.
9. The negative electrode active material of claim 1 , wherein the carbon-based layer is included in an amount of 0.5 wt % to 50 wt % based on a total weight of the negative electrode active material.
10. The negative electrode active material of claim 1 , wherein the oxide layer further comprises lithium silicate.
11. The negative electrode active material of claim 10 , wherein the lithium silicate comprises at least any one of Li 2 SiO 3 , Li 4 SiO 4 , or Li 2 Si 2 O 5 .
12. A negative electrode comprising a negative electrode active material of claim 1 .
13. A secondary battery comprising:
the negative electrode of claim 12 ;
a positive electrode;
a separator interposed between the positive electrode and the negative electrode; and
an electrolyte.
14. The negative electrode active material of claim 1 , wherein sphericity of the spherical carbon-based particle is from 0.6 to 0.9.
15. The negative electrode active material of claim 1 , wherein the LiF is included in an amount of 0.2 wt % to 5 wt % based on a total weight of the negative electrode active material.
16. The negative electrode active material of claim 1 , wherein the nano-particle is included in an amount of 2 wt % to 40 wt % based on a total weight of the negative electrode active material.